In semiconductor device manufacturing field, there have been many attempts to increase an integration density by means of miniaturization. Recently, there have been many attempts to increase an integration density per unit area by a method of stacking semiconductor devices which is called “three-dimensional packaging”.
Vertically stacked semiconductor devices (chips) include an electrode formed by penetrating a substrate and the semiconductor devices are electrically connected to each other via the electrode. When forming the electrode that penetrates the substrate, it is necessary to remove only a bottom portion of an insulating film formed within a hole perforated on the substrate while a sidewall portion of the insulating film remains.
As a method for removing only a bottom portion of an insulating film formed within a hole while a sidewall portion of the insulating film remains as described above, there is known a method that includes: forming a tapered hole in a substrate; attaching a tape onto a surface of the substrate; forming, in the tape, a hole having a diameter smaller than the tapered hole; and etching an insulating film formed at a bottom portion of the tapered hole through the hole in the tape (see, for example, Patent Document 1).
Further, there is known a method that includes: coating a sidewall portion of an insulating film formed within a hole with photoresist; and removing a bottom portion of the insulating film by etching.
Patent Document 1: PCT Publication No. 2004/064159